Objective: CXCL12 exerts a wide variety of chemotactic effects on cells. Evidence indicates that CXCL12, in conjunction with its receptor, CXCR4, promotes invasion and metastasis of tumor cells. Our objective was to explore whether the CXCL12-CXCR4 biological axis might influence biological behavior of pancreatic cancer cells. Methods: Miapaca-2 human pancreatic cancer cells were cultured under three different conditions: normal medium (control), medium + recombinant CXCL12 (CXCL12 group), or medium + CXCR4-inhibitor AMD3100 (AMD3100 group). RT-PCR was applied to detect mRNA expression levels of CXCL12, CXCR4, matrix metalloproteinase 2 (MMP-2), MMP-9, and human urokinase plasminogen activator (uPA). Additionally, cell proliferation and invasion were performed using CCK-8 colorimetry and transwell invasion assays, respectively. Results: CXCL12 was not expressed in Miapaca-2 cells, but CXCR4 was detected, indicating that these cells are capable of receiving signals from CXCL12. Expression of extracellular matrix-degrading enzymes MMP-2, MMP-9, and uPA was upregulated in cells exposed to exogenous CXCL12 (P<0.05). Additionally, both proliferation and invasion of pancreatic cancer cells were enhanced in the presence of exogenous CXCL12, but AMD3100 intervention effectively inhibited these processes (P<0.05). Conclusions: The CXCL12-CXCR4 biological axis plays an important role in promoting proliferation and invasion of pancreatic cancer cells.
Recently, we have indicated that microcystin-LR, a cyanobacterial toxin produced in eutrophic lakes or reservoirs, can increase invasive ability of melanoma MDA-MB-435 cells; however, the stimulatory effect needs identification by in vivo experiment and the related molecular mechanism is poorly understood. In this study, in vitro and in vivo experiments were conducted to investigate the effect of microcystin-LR on invasion and metastasis of human melanoma cells, and the underlying molecular mechanism was also explored. MDA-MB-435 xenograft model assay showed that oral administration of nude mice with microcystin-LR at 0.001-0.1 mg/kg/d posed no significant effect on tumor weight. Histological examination demonstrated that microcystin-LR could promote lung metastasis, which is confirmed by Matrigel chamber assay suggesting that microcystin-LR treatment at 25 nM can increase the invasiveness of MDA-MB-435 cells. In vitro and in vivo experiments consistently showed that microcystin-LR exposure increased mRNA and protein levels of matrix metalloproteinases (MMP-2/-9) by activating phosphatidylinositol 3-kinase (PI3-K)/AKT. Additionally, microcystin-LR treatment at low doses (≤25 nM) decreased lipid phosphatase PTEN expression, and the microcystin-induced invasiveness enhancement and MMP-2/-9 overexpression were reversed by the PI3-K/AKT chemical inhibitor LY294002 and AKT siRNA, indicating that microcystin-LR promotes invasion and metastasis of MDA-MB-435 cells via the PI3-K/AKT pathway.
High expression of the epidermal growth factor receptor (EGFR) has been implicated in the development of pancreatic cancer. Gefitinib is an orally active and selective EGFR-TKI (EGFR-tyrosine kinase inhibitor) that blocks signal transduction pathways responsible for the proliferation and survival of cancer cells, and other host-dependent processes promoting cancer growth. This study investigated the anticancer effect of gefitinib on human pancreatic cancer cells and the molecular mechanism involved. We first evaluated the effect of gefitinib on cell proliferation with MTT assay and the results demonstrated that gefitinib significantly inhibited the proliferation of pancreatic cancer cells. Flow cytometric analysis showed that gefitinib induced a delay in cell cycle progression and a G0/G1 arrest together with a G2/M block; these were associated with increased expression of p27 Kip1 cyclin-dependent kinase inhibitor combined with decreased expression of aurora B. Besides, luciferase reporter assay revealed that transcriptional mechanism was responsible for the down-regulation of aurora B protein by gefitinib. Overall, the results suggest a mechanistic connection among these events to provide new insights into the mechanism underlying the antiproliferative effect of gefitinib on pancreatic cancer and supplement a theory basis of gefitinib in clinical treatment of pancreatic cancer.
Despite tremendous advances in cancer treatment and survival rates, pancreatic cancer remains one of the most deadly afflictions and the fourth leading cause of cancer deaths in the world. Matrix Metalloproteinases (MMPs) are thought to be involved in cancer progression. Matrix metalloproteinase (MMP)-2 is known to play a pivotal role in tumor invasion, metastasis and angiogenesis, and validated to be the anticancer target. Inhibition of MMP-2 activity is able to reduce the cancer cell invasion and suppress tumor growth in vivo. Two novel peptides, M204C4 and M205C4, which could specially inhibit MMP-2 activity, were identified by a phage display library screening. We showed that M204C4 and M205C4 inhibited the activity of MMP-2 in a dose dependent manner in vitro. Two peptides reduced MMP-2 mediated invasion of the pancreatic cancer cell lines PANC-1 and CFPAC-1, but not affected the expression and release of MMP-2. Furthermore, these two peptides could suppress tumor growth in vivo. Our results indicated that two peptides selected by phase display technology may be used as anticancer drugs in the future.
BackgroundExtracts of the plant Hypericum perforatum L. have been traditionally used in folk medicine for the treatment of depressive disorders. Xanthone, a component of Hypericum perforatum L., has been shown to be effective in animal models of depression.ObjectiveWe investigated if 2 xanthone derivatives (1101 and 1105) were as effective as venlafaxine, which is a serotonin–norepinephrine reuptake inhibitor and was used as a positive control, in animal models of depression.MethodsA series of derivatives from xanthone were designed and synthesized. After preliminary experiments, 2 xanthone derivatives (1101 and 1105) were considered to be effective in our mouse depression model. To further determine their effects on depression, classical behavioral despair animal models (forced swim and tail suspension tests) were used to assess the efficacies of these derivatives, whereas venlafaxine hydrochloride was used as a positive control. Oral acute toxicity studies were used to determine if the derivatives were toxic in mice.ResultsThe oral acute toxicity studies of 2 xanthone derivatives (1101 and 1105) did not show any toxic effect until the dose at 1000 mg/kg body weight, and xanthone derivatives 1101 and 1105 resulted in a significant decrease of the immobility period (in seconds) compared with the untreated control group during the forced swim test with rats (dose = 12 mg/kg; P < 0.05) and mice (dose = 25 mg/kg; P < 0.001). At lower doses, derivatives 1101 and 1105 also decreased the immobility period of rats and mice during the forced swim test but significant differences were only found in mice compared with the untreated control group (P < 0.05). No difference was found between the groups treated with xanthone derivatives and the positive control group during the swimming period in both mice (dose = 25 mg/kg) and rats (dose = 12 mg/kg) (P > 0.05). In the tail suspension test, derivatives 1101 and 1105 produced marked effects with regard to the motion of mice (P < 0.01 or 0.001, respectively) and the derivatives were also noted to have some effects on rats at a dose of 12 mg/kg (P < 0.05). Compared with the positive venlafaxine control group, no differences were found between those treated with either derivative 1101 or derivative 1105 and venlafaxine (P > 0.05).ConclusionsWithin certain dose ranges, xanthone derivatives 1101 and 1105 have similar effects to venlafaxine hydrochloride in the treatment of depression as suggested by behavioral despair animal models using rats and mice.
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